Stop control motor for a sewing machine

ABSTRACT

At the termination of a typical sewing interval, a means for achieving a precise position (at a work station, etc.) for fabric or the like being sewn, comprising operating the sewing machine at a selected, known speed which has a correspondingly known stopping characteristic, and braking the machine at said speed with just the requisite braking effort necessary to terminate feed movement of the fabric just as it moves into position at said work station.

United States Patent [191 Boser et a1.

[ STOP CONTROL MOTOR FOR A SEWING MACHINE [76] inventors: Ronald Boser; Gerald Gluckin, both of 22 W. 26th St., New York, N.Y. 10010 22 Filed: Aug. 15,1974

21 Appl. No.: 497,746

[52] US. Cl. 112/130; 112/219 R v [51] Int. Cl. D058 37/04; DOSB 69/14 [58] Field of Search 112/219 B, 219 A, 219, 112/220, 221, 67, 87, 130

[56] References Cited UNITED STATES PATENTS 9/1949 Helmer 112/219 A 6/1960 Larys et a1. 112/219 A [4 1 Dec. 9, 1975 3,237,579 3/1966 Medynski et a1. 112/219 A 3,329,113 7/1967 Lewis et a1 112/130 3,616,770 l/1971 Blyther et a1. 112/130 X Primary Examiner-H. Hampton- Hunter Attorney, Agent, or FirmBauer & Amer [57] ABSTRACT At the termination of a typical sewing interval, a

means for achieving a precise position (at a work station, etc.) for fabric or the like being sewn, comprising operating the sewing machine at a selected, known speed which has a correspondingly known stopping characteristic, and braking the machine at said speed with just the requisite braking effort necessary to terminate feed movement of the fabric just as it moves into position at said work station.

6 Claims, 4 Drawing Figures U.S. Patent Dec. 9 1975 Sheet 1 of 2 3,924,550

US. Patent Dec. 9 1975 Sheet 2 of2 3,924,550

STOP CONTROL MOTOR FOR A SEWING MACHINE otherwise handle the work product or sewn fabric. To

automate the performance of these subsequent operations requires positioning the fabric at the conclusion of the sewing interval at a reasonably predictable location. However, the stopping characteristic of a sewing machine varies in accordance with its operating speed, and since varying operating speeds are required for sewing effectiveness, it has been difficult to achieve the necessary positioning control required for the referred to automation. If sewing is concluded at one speed it dictates a corresponding braking effort which, for positioning purposes, may not be suitable if sewing is concluded at a significantly different speed.

Broadly, it is an object of the present invention to provide a sewing machine stop control having effective positioning performance, which at the same time does not inhibit operating the machine during its normal interval of sewing service over a wide range of speeds, as required. Specifically, it is an object to achieve the positioning control required by exercising proper speed control over the sewing machine as it enters its terminal phase of a normal sewing interval, all as will be subsequently explained in greater detail.

A sewing machine stop control demonstrating objects and advantages of the present invention includes a first motor control means for operating the sewing needle drive motor at varying speeds so as to contribute to effective use thereof during a normal sewing interval of operation, a second motor control means operatively effective to operate said sewing needle drive motor at a known selected speed having a correspondingly known stopping characteristic, a first sensing means operatively effective preparatory to termination of the sewing operation of said sewing machine to automatically cause the operation thereof by said second motor control in preference to said first motor control so as to have said sewing needle drive motor operating at said known selected speed of operation, and a second sensing means operatively effective to terminate the sewing interval of said sewing machine while it is operating at said known selected speed, whereby said termination of operation occurs in accordance with said known stopping characteristic to contribute to termination in feed movement of the fabric being sewn at a selected location defining a work station.

The above brief description, as well as further objects, features and advantages of the present invention, will be more fully appreciated by reference to the following detailed description of a presently preferred, but nonetheless illustrative embodiment, in accordance with the present invention, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a front elevational view of a sewing machine and of a stop control for same according to the present invention;

FIG. 2 is a side elevational view projected from FIG. 1, illustrating further structural features;

FIG. 3 is a partial, perspective view, illustrating the sensing means of the stop control; and

FIG. 4 is an isolated view of an appropriate clutch means used for the stop control.

Reference is now made to the drawings, and in particular to FIG. 3, wherein the mode of operation is illustrated of the stop control of the present invention. Specifically, sewing machine 10 includes a vertically reciprocating sewing needle 12 and presser foot 14, both of which operate in a well-understood manner to produce stitching 16 in fabric urged by the feed dogs of the sewing machine in a feed path 18 past the sewing needle 12. The product being sewn in the illustrated instance will be understood to be an edge-finishing placket or similar folded'construction 20 having an unfinished or raw terminal edge 22. For purposes of illustrating the within invention, it is to be assumed that it is desirable that at the conclusion of the sewing interval of operation of the sewing machine 10, that the edges 22 be precisely located at a work station, preferably occupied by a cutting device, which device trims the edges 22 and thereby improves their appearance, and also simultaneously cuts the sewing thread 24. It will, of course, be understood that a great number of other operations can be performed at the work station other than those described, it being significant for the present invention that in order to perform the operations described, or any other operations, that the edges 22, be located precisely in cutting relation to the cutting device at the end of the sewing interval.

As illustrated in FIG. 3, sewing machine 10 has a guillotine-type cutting device 26 which, operating in a wellunderstood manner, will effectively trim the edges 22 provided that these edges are at the location 28 at the conclusion of thes'ewin g interval of the sewing machine 10. To this end, location 28 is established beneath the presser foot 14 and in vertical alignment 29 with the cutting device 26, such that the cutting stroke of the device 26 effectively trims the edges 22 at the location 28.

In accordance with the present invention, sewing machine 10 is provided with means for stopping the termination of sewing of the sewing machine 10 with the edges 22 accurately located at the work station or location 28. However, before describing the stop control of the present invention, it is helpful to understand that complicating the problem of stopping the sewing machine 10 while at the same time providing an accurate tenninal position for the edges 22, is the fact that each sewing machine has a different stopping characteristic which is related to its speed of operation. That is, a typical sewing machine customarily operates at different sewing speeds, such that in a normal interval of sewing, it might operate at various times at various speeds from 1,800 rpm to 8,500 rpm. Further, as should be readily appreciated, a sewing machine during its operation has many component parts which partake of revolving or reciprocating motion. The prime example of the former is the sewing machine balance wheel. Stopping this component part in any particular location during its rotation requires overcoming inertia and other such forces, which, as well understood, is a function of the rate of speed of rotation of the balance wheel.

Underlying the present invention is the recognition that the stopping characteristic of a sewing machine, as exemplified by sewing machine 10, although variable because it is a function of its speed of operation, is nevertheless predictable at any selected speed. It is therefore proposed according to the present invention to operate sewing machine at any speed necessary to contribute to its effective sewing, but that as the fabric being sewed approaches the work station 28, to impose on the operation of the sewing machine 10 a selected and known speed of operation which has a correspondingly known stopping characteristic. Thus, when the sewing machine 10 is then operating at a known and selected speed of operation, in connection with which it is also known what factors affect it in stopping, the present invention contemplates stopping or braking the sewing machine, with the result that the fabric being sewn stops at a precise location, which defines a work station at which cutting or some other essential operation is readily performed.

Still referring to FIG. 3, the above inventive concept is implemented by a pair of first and second sensing means 30 and 32, respectively, both mounted on the sewing machine 10, as at 34. Sensing means 30, 32, in a preferred form, consist of light fibrescopes through which beams of light 36 are effectively transmitted. That is, in practice, a light signal 36 is beamed through first sensing means 30 in a downward direction 38 toward the sewing machine work surface 40. As strip 20 moves in the feed direction 18, a light-reflecting material 42 is uncovered, and the light is then beamed in the reverse direction 44 to the fibrescope means 30. The returning light signal 44, as will be explained in detail subsequently, is effective in actuating a photocell or similar such control device, which, in turn, is effective in imposing a known, selected speed of sewing operation on the sewing machine 10. In the example illustrated, this known selected speed is preferably 1,100 rpm. Thus, while the sewing machine 10 could have conceivably operated at any speed between 1,800 rpm to 8,500 rpm up to the point where the light-reflecting material 42 is uncovered, after such uncovering, the light signal 44 is effective in causing operation of the sewing machine at the known speed of 1,100 rpm, and thus with a known stopping characteristic.

In accordance with the present invention, operation of the sewing machine 10 then proceeds at 1,100 rpm from the point where the first sensing means 30 is encountered until the light signal 36 of the second sensing means 32 is encountered, or, more particularly, until the strip edges 22 are urged through feed movement 18 and arrive at location 46. At location 46 it will be understood that movement of the edges 22 uncovers another light-reflecting material similar to material 42, and is thus effective in causing the light signal 48 to be returned and transmitted by the second sensing means 32 to a photocell or other such control device, which, in turn, causes the operation of a braking mechanism, which results in the termination of the operation of the sewing machine 10. It is, of course, significant that inasmuch as sewing machine 10 is operating at the known speed of 1,100 rpm at location 46, it is equally well known how much braking effort must be applied to overcome the inertia of the sewing machine balance wheel and other moving components. It should be readily appreciated that this known braking effort in turn results in the movement of the terminal end 22 of the strip 20 from location 46 for a precise, predictable distance which will result in the stopping of end 22 precisely at location or work station 28. This positioning, of course, occurs simultaneously with the termination of the sewing interval of the sewing machine 10, at which time cutting device 26 can then be operated through a descending cutting stroke 29 which results in trimming of the edges 22 and the severing of the sewing thread 24, and any other operation which it is desired to perform on the fabric being sewn.

In fact, even if there is no trimming or cutting being performed at the work station 28, it is a significant commercial advantage to have the terminal end 22 of strip 20 precisely located at station 28. Assuming that station 28 is immediately beyond the sewing station defined by the sewing needle 12, the next sewing interval performed on the succeeding strip 20 will of necessity start in close abutting relation to the terminal end of the preceding strip. Thus, strip materials can be prepared in connected relation, with an optimum minimum space between succeeding lengths, and then be separated preparatory to individual use. It will, of course, be understood that the stop control of the present invention, as just described, is capable of being used in many different ways in' cooperation with a sewing machine, and that the specific end use above described is not intended to be a limitation on the invention.

Reference is now made to FIGS. 1, 2 and 4 which illustrate exemplary structure for carrying out the abovedescribed mode of operation for a stop control according to the present invention. As illustrated, sewing machine 10 includes first and second motors 50 and 52, respectively, which are each operatively arranged to drive the sewing needle 12 through vertically reciprocating sewing strokes. Only one motor operates at any one time, motor 50 being the one which drives the sewing machine 10 during its normal sewing interval of operation at any selected speed between 1,800 rpm and 8,500 rpm. Motor 52, on the other hand, takes overwhen motor 50 isdisconnected, and will be understood to operate sewing machine 10 only at one speed of operation, namely the selected speed of 1,100 rpm. Since the drive connection between the motors 50, 52 and the sewing machine 10 are conventional, except that one drive is used in preference to the other, these drive connections will only be generally described.

The drive for motor 5 0, as best illustrated in FIGS. 1, 2, includes a motor shaft 54 having a pulley 56 mounted thereon. Located between the motors 50 and 52 is a clutch mechanism 58 which includes a pulley 60 in alignment with pulley 56. Entrained about the pulleys 56 and 60 is an endless pulley belt 62 which transmits rotation of motor 50 which powers driving pulley 56 to the driven pulley 60.

Clutch 58 also includes a shiftable pulley 64 which is in general alignment with pulley 66 of the sewing machine 10. An endless pulley belt 68 is entrained about the pulleys 64, 66. Thus, when pulley 64 is engaged with pulley 60 and the latter is driven in rotation by motor 50, this results in power being transmitted via pulley belt 68 to pulley 66 and thus results in the operation of sewing machine 10 at a speed of operation which is related to the speed of operation of the motor 50.

The drive of motor 52 similarly includes a motor shaft 70 mounting a pulley 72. Aligned with pulley 72 is pulley 74 of the clutch 58, and entrained about these two pulleys is an endless pulley belt 76. Clutch 58, op-

erated in a 'well understood manner, is effectively utilized to select the operating speed for the sewing machine by virtue of being used to select which of the two pulleys, as between pulley 60 and 74, the sliding pulley 64 establishes engagement with. Specifically, it is pulley 64 which, as previously indicated, must be in engagement with pulley 60 in order for the motor 50 to power the sewing machine 10. This is the drive condition during normal sewing operation of the sewing machine 10. Pulley 64, however, is readily disengaged from pulley 60 and instead engaged with pulley 74 when motor 52 takes over. During this drive, motor 52 is operatively effective, via the pulley belts 76 and 68, to operate the sewing machine 10.

Still referring to FIGS. 1, 2, for completeness sake, it should be noted that while motor 50 is driving the sewing machine 10, that the sewing machine operator is able, in a well understood manner, to manipulate a foot treadle 78. Treadle 78 is connected via conventional linkage 80 to motor 50 so as to change its output gear ratio, or the like, which results in variation in the speed of rotation of the motor 50. As a consequence, the output of this motor can range from 1,800 rpm to 8,500 rpm.

Attention is now directed to FIG. 4 which illustrates the structural details of the clutch mechanism 58 which, as already generally described, permits the selection of one of the two motors 50 and 52 to power the sewing machine 10 in sewing operation. Clutch mechanism 58 includes a u shaped body 82 having two spaced apart legs 84 and 86 mounting a bar 88 having limited lateral movements 90. Joumaled for rotation on bar 88 is pulley 64 having opposite friction surfaces 92 and 94. Cooperating with the pulley 64 are the previously noted pulleys 60 and 74, respectively, each journaled for rotation on hubs 96 extending laterally from the legs 84 and 86. On the inner surfaces of the pulleys 60 and 74 are friction surfaces 98 and 100, respectively, in facing relation to the friction surfaces 92 and 94 of the pulley 64. Thus, shifting movement of support 88 in the direction which results in the engagement of the friction surfaces 98 and 92 completes the drive connection between the motor 52 and the sewing machine 10, whereas reverse direction movement of the support 88 results in disengagement of the friction surfaces 98 and 92 and in engagement of the friction surfaces 94 and 100. The engagement of the friction surfaces 94, 100 results in a drive connection being completed via the pulley 60 and 64, and thus in the powering of the sewing machine 10 by the motor 50.

Any appropriate technique may be utilized to achieve the control movements 90 for the clutch 58. As illustrated in FIG. 4, one way of achieving this is to utilize a solenoid-operated air cylinder 102 having a piston rod 104 operatively connected, as at 106, to a link 108 pivotable about a pivot 110. Bifurcated extensions 112 engages a lateral pin 1 14 of bar 88 and thus transmit the piston movements 116 to the bar 88 as lateral movements 90.

Shown diagrammatically in FIG. 4 are photocells 118 which are electrically connected via a conductor 120 to the air cylinder 102, such that pulses from the photocells 118 are effective in causing the aforesaid piston movements 116 which result in the appropriate directional shifting movements 90 in the middle pulley 64. The photocells 118 will be understood to be operated by the first and second sensing means 30 and 32 previously described in detail in connection with FIG 3.

Completing the construction of the stop control of the present invention is an appropriate braking means for terminating the operation of the sewing machine 10. As illustrated in FIGS. 1, 2, this braking means, generally designated 122, includes a braking disc 124 mounted on the free end of a reduced diameter extension of the motor shaft 70. Cooperating with the disc 124 is a flexible brake shoe 126 wrapped in braking relation about the disc 124 and connected at one end to a solenoid 128, which solenoid also will be understood to be operated into braking service by a signal pulse from the photocells 118. More particularly, solenoid 128 is operated by the second encountered sensing means 32, and thus when the returning light signal 48 operates the particular photocell 118 which is in connected controlling relation to the solenoid 128, this causes its operation and in turn'results in the imposition of a braking effort on the motor 52. As already described, motor 52 is the motor which drives the sewing machine 10 during the terminal portion of the normal sewing interval. Motor 52 operating at the selected speed of 1,100 rpm hasa known stopping characteristic which brake 122 is readily capable of managing, so that feed movement of the strip 20 occurs precisely at the location of the work station 28, all in the manner described in detail, particularly in connection with FIG. 3.

A latitude of modification, change and substitution is intended in the foregoing disclosure, and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

What is claimed is:

1. In combination, a sewing machine having a sewing needle and motor means for driving said sewing needle through vertically reciprocating sewing strokes, said motor means having stopping characteristics related to its operating speeds, and a stop control for said sewing machine comprising a first motor control means for operating said sewing needle drive motor means at varying speeds so as to contribute to effective use thereof during a normal sewing interval of operation, a second motor control means operatively effective to operate said sewing needle drive motor means at a known selected speed having a correspondingly known stopping characteristic, a first sensing means operatively effective preparatory to termination of the sewing operation of said sewing machine to automatically cause the operation thereof by said second motor control means in preference to said first motor control means so as to have said sewing needle drive motor means operating at said known selected speed of operation, and a second sensing means operatively effective to terminate the sewing interval of said sewing machine while it is operating at said known selected speed, whereby said termination of operation occurs in accordance with said known stopping characteristic to contribute to termination in feed movement of the fabric being sewn at a selected location defining a work station.

2. The sewing machine stop control as defined in claim 1 wherein said motor means comprises two separate motors and a clutch means for selectively completing a drive between only one of said two motors and said sewing machine.

3. The sewing machine stop control as defined in claim 2 wherein said first and second sensing means are photocells disposed along the path travelled by tle fabric being fed to said sewing needle.

4. A stop control for a sewing machine having a vertically reciprocating sewing needle and a high speed motor operatively arranged to provide rapid sewing service of said sewing needle during the normal sewing interval of operation of said sewing machine, said stop control comprising means defining a feed path past said sewing needle for edge-finishing material in strip form being stitched to a body fabric by said sewing needle, a work station established at a strategic location along said feed path immediately beyond said sewing needle, a cutting device disposed at said work station operatively effective to sever said strip at a selected cut-off location therealong at the termination of said sewing interval, a low speed motor operatively arranged to power said sewing needle in sewing operation in substitution for said high speed motor, a first encountered sensing means located along said feed path in advance of said sewing needle by a selected amount sufficient to cause the powering of said sewing needle by said low speed motor instead of by said high speed motor before 8 said strip cut-off location moves into said work station, and a second encountered sensing means located between said first encountered sensing means and said work station operatively connected to terminate feed movement of said edge-finishing strip with said cut-off location thereof in cutting relation to said cutting device at said work station and to cause cutting operation of said cutting device, whereby the terminal portion of the feed movement of said edge-finishing strip is advantageously automatically at a low speed to facilitate the stopping and cutting of said strip.

5. The sewing machine stop control as defined in claim 4 including a clutch means operated by said first encountered sensing means for disconnecting the drive connection to said sewing machine of said high speed motor and completing the drive connection for said low speed motor.

6. The sewing machine stop control as defined in claim 5 wherein said first and second sensing means are photocells. 

1. In combination, a sewing machine having a sewing needle and motor means for driving said sewing needle through vertically reciprocating sewing strokes, said motor means having stopping characteristics related to its operating speeds, and a stop control for said sewing machine comprising a first motor control means for operating said sewing needle drive motor means at varying speeds so as to contribute to effective use thereof during a normal sewing interval of operation, a second motor control means operatively effective to operate said sewing needle drive motor means at a known selected speed having a correspondingly known stopping characteristic, a first sensing means operatively effective preparatory to termination of the sewing operation of said sewing machine to automatically cause the operation thereof by said second motor control means in preference to said first motor control means so as to have said sewing needle drive motor means operating at said known selected speed of operation, and a second sensing means operatively effective to terminate the sewing interval of said sewing machine while it is operating at said known selected speed, whereby said termination of operation occurs in accordance with said known stopping characteristic to contribute to termination in feed movement of the fabric being sewn at a selected location defining a work station.
 2. The sewing machine stop control as defined in claim 1 wherein said motor means comprises two separate motors and a clutch means for selectively completing a drive between only one of said two motors and said sewing machine.
 3. The sewing machine stop control as defined in claim 2 wherein said first and second sensing means are photocells disposed along the path travelled by the fabric being fed to said sewing needle.
 4. A stop control for a sewing machine having a vertically reciprocating sewing needle and a high speed motor operatively arranged to provide rapid sewing service of said sewing needle during the normal sewing interval of operation of said sewing machine, said stop control comprising means defining a feed path past said sewing needle for edge-finishing material in strip form being stitched to a body fabric by said sewing needle, a work station established at a strategic location along said feed path immediately beyond said sewing needle, a cutting device disposed at said work station operatively effective to sever said strip at a selected cut-off location therealong at the termination of said sewing interval, a low speed motor operatively arranged to power said sewing needle in sewing operation in substitution for said high speed motor, a first encountered sensing means located along said feed path in advance of said sewing needle by a selected amount sufficient to cause the powering of said sewing needle by said low speed motor instead of by said high speed motor before said strip cut-off location moves into said work station, and a second encountered sensing means located between said first encountered sensing means and said work station operatively connected to terminate feed movement of said edge-finishing strip with said cut-off location thereof in cutting relation to said cutting device at said work station and to cause cutting operation of said cutting device, whereby the terminal portion of the feed movement of said edge-finishing strip is advantageously automatically at a low speed to facilitate the stopping and cutting of said strip.
 5. The sewing machine stop control as defined in claim 4 including a cLutch means operated by said first encountered sensing means for disconnecting the drive connection to said sewing machine of said high speed motor and completing the drive connection for said low speed motor.
 6. The sewing machine stop control as defined in claim 5 wherein said first and second sensing means are photocells. 